/**
 * Copyright (C) 2002-2015   The FreeCol Team
 * <p>
 * This file is part of FreeCol.
 * <p>
 * FreeCol is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 * <p>
 * FreeCol is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * <p>
 * You should have received a copy of the GNU General Public License
 * along with FreeCol.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.sf.freecol.client.gui.panel;

import java.awt.Component;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.logging.Logger;

import net.sf.freecol.common.model.TradeRoute;
import net.sf.freecol.common.model.Unit;


/**
 * This class provides common functionality for sub-panels of a
 * PortPanel that display UnitLabels.
 */
public abstract class UnitPanel extends MigPanel
        implements PropertyChangeListener
{

    private static final Logger logger = Logger.getLogger( UnitPanel.class.getName( ) );

    /** The panel containing the units to display. */
    private PortPanel portPanel;

    /** Whether this panel is editable. */
    private final boolean editable;


    /**
     * Create a unit panel.
     *
     * @param portPanel A <code>PortPanel</code> to supply units.
     * @param name An optional name for the panel.
     * @param editable True if the panel can be edited.
     */
    public UnitPanel( PortPanel portPanel, String name, boolean editable )
    {
        if ( portPanel == null ) throw new RuntimeException( "Null port panel." );
        this.portPanel = portPanel;
        this.editable = editable;
        setName( name );
    }


    /**
     * Initialize this unit panel.
     */
    public void initialize( )
    {
        cleanup( );
        addPropertyChangeListeners( );
        update( );
        Unit active = portPanel.getGUI( ).getActiveUnit( );
        if ( active != null && active.isCarrier( ) ) setSelectedUnit( active );
    }

    /**
     * Clean up this unit panel.
     */
    public void cleanup( )
    {
        removePropertyChangeListeners( );
    }

    /**
     * Add any property change listeners.
     */
    protected void addPropertyChangeListeners( )
    {
        // do nothing
    }

    /**
     * Remove any property change listeners.
     */
    protected void removePropertyChangeListeners( )
    {
        // do nothing
    }

    /**
     * Update this unit panel.
     */
    public void update( )
    {
        removeAll( );

        if ( portPanel != null )
        {
            for ( Unit unit : portPanel.getUnitList( ) )
            {
                if ( ! accepts( unit ) ) continue;

                UnitLabel unitLabel
                        = new UnitLabel( portPanel.getFreeColClient( ), unit );
                TradeRoute tradeRoute = unit.getTradeRoute( );
                if ( tradeRoute != null )
                {
                    unitLabel.setDescriptionLabel( unit
                                                           .getDescription( Unit.UnitLabelType.NATIONAL )
                                                           + " (" + tradeRoute.getName( ) + ")" );
                }
                if ( editable )
                {
                    unitLabel.setTransferHandler( portPanel.getTransferHandler( ) );
                    unitLabel.addMouseListener( portPanel.getPressListener( ) );
                }
                add( unitLabel );
            }
        }

        selectLabel( );
        revalidate( );
        repaint( );
    }


    /**
     * Get the port panel that supplies units to this panel.
     *
     * @return The <code>PortPanel</code>.
     */
    public PortPanel getPortPanel( )
    {
        return portPanel;
    }

    /**
     * Is this panel editable?
     *
     * @return True if the panel is editable.
     */
    public boolean isEditable( )
    {
        return editable;
    }

    /**
     * Can this panel accepts the given Unit.
     *
     * @param unit The <code>Unit</code> to check.
     * @return True if the unit can be added.
     */
    public abstract boolean accepts( Unit unit );

    /**
     * Select a UnitLabel based on some criterion.
     */
    public void selectLabel( )
    {
        // Default to doing nothing
    }

    /**
     * Select a given unit.
     *
     * @param unit The <code>Unit</code> to select.
     * @return True if the selection succeeds.
     */
    public boolean setSelectedUnit( Unit unit )
    {
        for ( Component component : getComponents( ) )
        {
            if ( component instanceof UnitLabel )
            {
                UnitLabel label = ( UnitLabel ) component;
                if ( label.getUnit( ) == unit )
                {
                    getPortPanel( ).setSelectedUnitLabel( label );
                    return true;
                }
            }
        }
        return false;
    }


    // Interface PropertyChangeListener

    /**
     * {@inheritDoc}
     */
    @Override
    public void propertyChange( PropertyChangeEvent event )
    {
        logger.finest( getName( ) + " change " + event.getPropertyName( )
                               + ": " + event.getOldValue( )
                               + " -> " + event.getNewValue( ) );
        update( );
    }


    // Override Component

    /**
     * {@inheritDoc}
     */
    @Override
    public void removeNotify( )
    {
        super.removeNotify( );

        removePropertyChangeListeners( );
        portPanel = null;
    }
}
